[CentOS] CentOS 5.8 crash/freeze running VMware

On 06/29/2012 09:52 AM, Michael Eager wrote:
> On 06/28/2012 06:33 PM, Ted Miller wrote:
>> On 06/28/2012 12:45 PM, Michael Eager wrote:
>>> Hi --
>>>
>>> I have a server running CentOS 5.8.  It has a 6-core AMD processor,
>>> 16Gb memory, and a RAID 5 file system.  It serves as both a file server
>>> and to run several VMware virtual machines.  The guest machines run
>>> Windows 7 and various versions of Linux.
>>>
>>> The system is running the latest version of VMware Workstation.
>>> Until recently, I started VMs using the VMware Workstation GUI.
>>> The system has been very stable and seldom crashes.
>>>
>>> Recently, I set up an init script to start several VMs at boot
>>> time using the vmrun command.  This appeared to work correctly,
>>> but the system has become unstable, freezing at various times.
>>> When the system freezes, there is no console response and it
>>> does not respond to a ping.  There is nothing in syslog to
>>> indicate any error.
>>>
>>> The script started 8 VMs.  I've cut back to now running 4 VMs
>>> and the system appears stable.
>>>
>>> Is there some relation between the number of cores and the number
>>> of VMs one can run?
>>>
>>> Is there something else which might cause the system to crash
>>> when running multiple VMs?
>>>
>>> Any suggestions to identify why the system crashed?
>>>
>> Are you staggering the startups of the VMs?  The server may be choking
>> trying to boot 8 machines at once.  I suggest starting a VM every 30-60
>> seconds, so that you aren't trying to boot all 8 at once.  Don't know if it
>> will help, but it might.
> The crashs happen long after boot time when all of the VMs are running.
>
> (Actually, startup goes very smoothly, with the VMs starting in parallel
> in the background while system boot completes.)

This sounds like the issue with the machine running out of memory and
the Out of Memory killer actually killing one of the VMWare instances.

My experience with this on a very good machine was that there was enough
memory, but it was timing that was causing the issue.  The machine did
not respond quickly enough to the memory request and the OOM Killer then
acted.

How I solved my problem was to reserve more memory as unused with this
memory variable:

I have had issues with VMWare host server and running out of memory,
maybe try setting this variable in sysctl.conf:

vm.min_free_kbytes=65536

(that will maintain 64MB of free RAM and should allow for enough time to
prevent OOM kills)




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